The present invention relates to a plasma processing apparatus for performing the etching of a substrate and the surface processings such as thin-film formation by using plasma. More particularly, it relates to an inductively-coupled plasma processing apparatus.
Of the today's semiconductor-device markets, the non-volatile RAM (Random Access Memory) market is now expanding. Above all, such non-volatile RAMs as FeRAM (Ferroelectric Random Access Memory) and MRAM (Magnetic Random Access Memory) are under enthusiastic development in each company. This is because FeRAM and MRAM have advantages in their low power consumption and high-speed operation.
The mass production of FeRAM and MRAM requires the etching of non-volatile materials such as PZT (Lead Zirconate Titanate) for FeRAM and CoFe for MRAM. As the units for etching these non-volatile materials, for example, an inductively-coupled plasma processing apparatus is used in the semiconductor-device fabrication field. In this inductively-coupled plasma processing apparatus, a process gas is inserted into a plasma processing chamber. Moreover, plasma is generated from this process gas by causing a radio-frequency current to flow along an induction coil that is deployed outside the plasma processing chamber.
This inductively-coupled plasma processing apparatus is based on the following scheme: The power is supplied to the plasma in such a manner that an induced current is induced in the plasma by causing the radio-frequency current to flow along the induction coil deployed outside the plasma processing chamber. This scheme commonly prevails, because it allows implementation of the plasma processing apparatus whose apparatus configuration is comparatively simple. Furthermore, the merits resulting from utilizing the plasma are as follows: The promotion of chemical reactions by high-energy electrons becomes implementable, and directivity-equipped processings become implementable by irradiating a process plane on the wafer surface with high-energy ions.
As this inductively-coupled plasma processing apparatus, a plasma processing apparatus is used which is disclosed in JP-A-2004-235545. As is exactly disclosed in JP-A-2004-235545, a cone-shaped and dielectric-composed bell-jar, which constitutes the upper portion of the plasma processing chamber, is set up in this chamber. Moreover, an induction coil for generating plasma is set up on the upper portion of this bell-jar. A cone-shaped Faraday shield is set up between the bell-jar and the induction coil. Applying a high voltage to this Faraday shield makes it possible to control reaction byproducts that adhere onto the inner wall of the bell-jar.
Also, as a similar plasma processing apparatus, a plasma processing apparatus is used which is disclosed in JP-A-2011-253916 (corresponding to U.S. Patent Publication No. 2011/297320). JP-A-2011-253916 is constituted based on a similar structure to JP-A-2004-235545. Namely, divided Faraday shields are set up between the dielectric-composed bell-jar and the plasma-generation-use induction coil. The voltage control over these divided Faraday shields can be performed independently of each other. This condition makes it possible to control the reaction byproducts more accurately. The use of these divided Faraday shields allows implementation of the processing apparatus that is superior in the mass-production property and the etching performance.